Question: Which of the following numbers is a multiple of 4? ${41,51,78,94,108}$
Solution: The multiples of $4$ are $4$ $8$ $12$ $16$ ..... In general, any number that leaves no remainder when divided by $4$ is considered a multiple of $4$ We can start by dividing each of our answer choices by $4$ $41 \div 4 = 10\text{ R }1$ $51 \div 4 = 12\text{ R }3$ $78 \div 4 = 19\text{ R }2$ $94 \div 4 = 23\text{ R }2$ $108 \div 4 = 27$ The only answer choice that leaves no remainder after the division is $108$ $ 27$ $4$ $108$ We can check our answer by looking at the prime factorization of both numbers. Notice that the prime factors of $4$ are contained within the prime factors of $108$ $108 = 2\times2\times3\times3\times3 4 = 2\times2$ Therefore the only multiple of $4$ out of our choices is $108$. We can say that $108$ is divisible by $4$.